[Dying and death in an acute-care medical hospital]

Nowadays, more people seem to die in hospitals or other establishments than in their own homes. The following paper reports on 50 consecutive cases of death that occurred in a clinic of internal medicine. The analysis concentrated on the circumstances, the symptoms and the treatment of the patients during the 12 h. preceding and immediately before death as well as on the opinion of the relatives and the attending staff. A questionnaire registered the different opinions. Nearly a third of these deaths occurred after a fairly short hospitalization time. Death was not always the result of a long illness and it involved also young people. Most of the patients died in their hospital room, in the presence of their relatives and/or of the attending staff. They were mostly unconscious during the moments preceding their death. Terminal symptoms such as pain, anxiety, shortness of breath or thirst were largely kept under control. The relatives and concerned people were, as far as possible, informed about the grievance and the fatal issue of the patient's illness. Their reactions were diverse. Most relatives were satisfied with the treatment and care given to the hospitalized patient. The doctors and nursing staff considered their working together as being better than usually expected. Clear therapeutical concepts, appropriate palliative care as much as optimal communication are important requirements for a good treatment of the dying. The following results allow us to question many a prejudice concerning death in a hospital surrounding, but also show us possibilities of improvement. So we should sometimes question ourselves about the sense and the need of certain nursing interventions. We should spend more time during our medical training on the question of palliative care and on the problem of the relationship of doctors to death and to the dying. We feel that establishing a "science of death" or a segregation of the dying in specialized institutions makes no sense.

Use of preoperative vascular embolisation in spinal metastasis resection

Preoperative selective embolisation was carried out on 17 patients with spinal metastases from various primary tumours. There was a significant reduction in the blood loss (2088 ml) and infusion volume requirement (3500 ml) and more favourable postoperative haemoglobin (Hb) development compared with the non-embolised but otherwise identical control group. The reduced intraoperative bleeding manifested itself in the form of greater clarity and a less complicated intraoperative course. Particularly with a dorsal approach, the reduced bleeding permitted more exact preparation and more extensive tumour resection. Preoperative embolisation is thus a valuable aid in spinal metastasis resection. Given suitable indications and exact positioning of the embolising material, no significant complications should arise. The method as a whole calls for close collaboration between interventional radiologists and spinal orthopaedists.

A mouse model of herpes simplex virus encephalitis: diagnostic brain imaging by magnetic resonance imaging

Herpes simplex virus encephalitis is a severe sporadic encephalitis in man with high mortality and morbidity. A critical step in the establishment of therapy is early diagnosis. Magnetic resonance imaging is a noninvasive, accurate diagnostic test for the detection of central nervous system disease. In an effort to monitor morphological changes in vivo we present a new diagnostic neuroimaging model of experimental herpes simplex virus encephalitis. A mouse model of herpes simplex virus encephalitis was used. 40 SJL mice were intranasally inoculated with an infectious dose of wild-type strain HSV-I F. Morphological abnormalities were studied by cranial magnetic resonance imaging (MRI). These findings were correlated with sequential neuropathological studies. 95% of animals developed cerebral abnormalities on MRI. resembling human HSVE. Areas of increased signal intensity on T2-weighted sequences and focal pathological contrast enhancement were mostly found in the frontal and temporal lobes and thalamic and cerebellar regions. All animals with MRI abnormalities had neuropathological signs of neuronal degeneration and reactive astrocytosis in corresponding regions. The described monitoring system offers a new approach for studies on neurovirulence and therapeutic strategies.

Low-grade astrocytoma: treatment with conventionally fractionated stereotactic radiation therapy

PURPOSE

To assess the efficacy of fractionated stereotactic radiation therapy for low-grade astrocytoma in terms of improvements to therapeutic ratio, patient survival, and quality of life.

MATERIALS AND METHODS

Since 1987, 32 patients with inoperable grade II astrocytoma were irradiated. Stereotactic radiation therapy was given only to patients with progressive symptoms. The mean total dose applied was 59.8 Gy (range, 54.0-65.0 Gy).

RESULTS

Four years after therapy, the overall survival rate calculated with Kaplan-Meier analysis was 76%. Median progression-free survival was 48 months. On the basis of clinical symptoms, 91% (29 of 32) of patients showed improvement or stable disease after stereotactic radiation therapy. Eleven local failures were observed, 10 of which were within the planning target volume; one patient had a continuously enlarging mass. Acute toxic effects of radiation did not exceed grade II of the World Health Organization classification. Two patients developed reversible contrast enhancement without clinical symptoms on MR images within 1 year after stereotactic radiation therapy.

CONCLUSION

Stereotactic radiation therapy for grade II astrocytoma appears to improve patients' quality of life or stabilize disease and is not correlated with marginal misses.

[Is a clinical positional control for nasogastric tubes good enough? A prospective study of 43 patients]

OBJECTIVE

Nasoenteric tubes are usually introduced blindly by nursing staff, i.e. without visual or radiological control. A prospective study was undertaken to determine how often such blind procedure results in potentially dangerous tube placement and how often such faulty positioning remains undetected in a standardised clinical check.

PATIENTS AND METHODS

43 patients (23 men, 20 women; age 24-90 years) requiring the introduction by nursing staff of a nasoenteric tube were studied, 12 in an intensive care unit (seven intubated) and 31 in an ordinary ward. At most 24 hours after the customary check of the tube's position by the nursing staff (air injection with epigastric auscultation), specially experienced medical and nursing personnel determined and recorded the tube's placement in a standardised manner. Subsequent radiological examination documented the position.

RESULTS

All 43 tubes lay in the gastrointestinal tract. Only one tube was in a potentially dangerous position in the lower end of the oesophagus, as had already been diagnosed by the examiners. Of four other tubes which were not optimally placed (three in the region of the cardia, one in the duodenum) three were found to be "not correctly placed" by the clinical check, and one was detected only radiologically.

CONCLUSIONS

Clinical control of a nasoenteric tube's position suffices in most instances. Checking the position further by an experienced person adds to safety. The study's findings suggest that radiological control can be safely limited to cases in which there was a problem in positioning the tube or the clinical control was unclear.

Improved visualization of breast lesions with gadolinium-enhanced magnetization transfer MR imaging

A pulse sequence with magnetization transfer as the main contrast mechanism (MT-FLASH) was developed for improved imaging of breast lesions that requires neither fat suppression nor postprocessing. After optimization of the sequence in phantom and volunteer studies, a clinical pilot study with 14 patients was performed. In carcinomas the relative signal increase after Gd-DTPA administration was on average 34% in MT-FLASH images compared with 169% in conventional T1-weighted (T1W) three-dimensional FLASH images. In MT-FLASH images, all lesions demonstrated a signal intensity higher than that of fat; in T1W images, all lesions have a lower signal intensity. The average postcontrast carcinoma-to-fat contrast-to-noise ratios were +11.6 and -14.2, respectively. The conspicuity of 12 of 13 carcinomas was improved in postcontrast MT-FLASH imaging enables excellent visualization of Gd-DTPA-enhancing breast lesions.

Prospective evaluation of a semiquantitative dip slide method compared with quantitative bacterial cultures of BAL fluid

BACKGROUND

Quantitative bacteriologic workup of BAL fluid (BALF) has evolved as a sensitive and specific technique for the diagnosis of bacterial pneumonia. Conventional quantitative cultures are expensive, time-consuming, and often unavailable on a 24-h basis. Therefore, we evaluated a dip slide method for the semiquantitative measurement of bacterial cultures in BALF specimens and compared the results with those from conventional quantitative cultures.

METHODS

Fifty BALF specimens from 45 patients with suspected pulmonary infection were examined prospectively with both methods. We compared the microbiologic results of conventional quantitative cultures with those of the dip slide method that is commercially available for blood cultures. Cost-effectiveness analysis of both methods was performed.

RESULTS

In 37 BALF specimens, 64 bacterial strains were detected with both techniques. The dip slide method and conventional cultures showed a high correlation with respect to the colony counts of the individual organisms per milliliter BALF (r=0.935; p= 0.0001) and the sum of colony counts in individual patients (r=0.947; p=0.0001). Although five strains were not detected by the dip slide technique, the diagnostic accuracy was not influenced. In 13 BALF samples, there was no growth of bacteria with both techniques. While the diagnostic yield of both methods was similar, the dip slide technique was 44 to 66% less expensive than conventional cultures.

CONCLUSIONS

The examination of BALF with a clip slide method is highly comparable to conventional quantitative culture techniques, less expensive, and can be used independently of a specialized microbiology laboratory on a 24-h basis.

[Experimental studies on the role of intramedullary alignment rods in the etiology of fat embolisms in knee endoprostheses]

Fat embolism syndrome (FES) during implantation of an uncemented resurfacing type of total knee replacement is the leading cause of postoperative mortality. A possible explanation might be the insertion of a solid intramedullary alignment rod, resulting in an intrafemoral pressure increase. On 45 cadaveric human femora we measured the resulting intramedullary pressure during insertion of three different alignment rods: a solid rod and a hollow shaped guiding rod, both 10 mm in diameter, and a fluted alignment rod of 8.5 mm in diameter. The highest intramedullary pressures occurred after placement of a solid 10 mm alignment rod (3.77 +/- 0.44 bar), followed by a fluted 8.5 mm rod (2.53 +/- 0.28 bar). In both cases, the increased pressure led to an extrusion of bone marrow contents through the venous system of the proximal femur. The least increase occurred after insertion of a hollow shaped alignment rod (0.26 +/- 0.03 bar) without any fat extrusion. Our study confirms the hypothesis that insertion of solid intramedullary alignment rods during preparation of the femoral shaft results in a dangerous pressure increase, so that embolization can occur. To minimize the risk of a FES, instruments should be modified in a manner, that only hollow shaped alignment rods are used.

Characteristics of Bordetella hinzii strains isolated from a cystic fibrosis patient over a 3-year period

Over a 3-year period, an adult cystic fibrosis patient underwent eight episodes of pulmonary exacerbation of his disease. At least one of two different strains of Bordetella hinzii could be isolated from sputum samples in every instance. The differentiation of B. hinzii from related taxa and its role as an etiologic agent of infections are discussed. The two isolates of B. hinzii reported are the third and fourth human-derived strains described in the literature.

[Compliance with nasal positive pressure (CPAP) in obstructive sleep apnea syndrome]

Continuous positive airway pressure (CPAP) is the treatment of first choice for obstructive sleep apnea syndrome (OSAS). The effect of this treatment is highly dependent on patient compliance. To identify factors associated with compliance, a questionnaire was sent to 53 patients with OSAS for whom CPAP treatment had been prescribed. Response rate was 96%. 45 of 51 patients (88%) stated they had been on CPAP for a period of 30 to 2340 (median 292) days. 43 of the 51 patients (84%) who used CPAP regularly, defined as at least 4 hours nightly on 5 nights per week, were considered as compliant with the prescribed treatment. They did not differ from non-compliant patients either in initial symptom score or in apnea/hypopnea index at initial presentation. The most consistent factor associated with compliance was symptomatic improvement with CPAP. Side effects were more common in non-compliant patients. Symptomatic improvement during an initial trial with CPAP should be considered when starting definitive treatment, in order to optimize compliance.

Effect of radiation on blood volume in low-grade astrocytomas and normal brain tissue: quantification with dynamic susceptibility contrast MR imaging

OBJECTIVE

The purpose of this study was to determine whether it is possible to measure radiation-induced changes in blood volume in low-grade astrocytomas and in normal brain tissue.

SUBJECTS AND METHODS

The passage of a bolus of gadopentetate dimeglumine was monitored on a series of 55 T2*-weighted simultaneous dual fast low-angle shot MR images with a standard 1.5-T MR imaging system. Absolute blood volumes were calculated as the area under the tissue concentration-time curve in regions of interest and normalized to the arterial input function. We performed 41 examinations on 19 patients with grade II astrocytomas. For comparison, 13 patients were studied after whole-brain irradiation.

RESULTS

A reduction in blood volume (mean +/- SD in milliliters per 100 g) within the tumors from 12.2 +/- 8.7 to 6.5 +/- 5.3 after fractionated conformation radiotherapy was detected, although there was no consistent pattern in different patients. An insignificant reduction was noted in normal gray (9.2 +/- 2.8 to 7.4 +/- 3.2) and white (4.4 +/- 1.9 to 4.1 +/- 2.3) matter outside the target volume. Conversely, we observed a significantly lower blood volume in gray (6.3 +/- 1.2) and white (3.1 +/- 1.0) matter after whole-brain radiotherapy.

CONCLUSION

Our results show that a reduction of blood volume in astrocytomas and normal brain tissue after radiotherapy can be quantified by use of dynamic susceptibility contrast MR imaging. Thus, functional monitoring of tumor response and of normal tissue effects becomes possible.

Chondropathia patellae and knee muscle control. An electromyographic study

The activity of knee-related muscles was registered via exercising on a bicycle ergometer by 17 patients with clinically diagnosed chondropathia patellae. M. quadriceps activity was shorter and the hamstring activity longer in the chondropathy group compared with a matched healthy control group. The changes in m. quadriceps occurred to an almost equal extent in lateral and medial sections. In five patients with unilateral complaints, the electromyographic changes were nevertheless noted on both sides. The study shows that chondropathia patellae involves a change in muscle control affecting not only the knee extensors but also the hamstrings. Through the changed innervation pattern the coactivation phase, i.e. the phase of simultaneous activation of knee flexors and extensors at the end of the extension phase, takes place at a higher angle of flexion. Physiotherapy should involve all knee-related muscles and should include not only isometric but also dynamic exercises.

Safety of intrauterine contraceptive devices during MR imaging

Three intrauterine contraceptive devices (IUD) were examined in an experimental in vitro setup to test their MR compatibility: Multiload CU375. Nova T (containing copper and silver), and Gyne T. The devices were fixed in a polyacrylamide gel and exposed to the magnetic field and the radiofrequency (RF) of standard MR sequences (spin-echo, turbo-spin-echo, turboFLASH, and magnetization transfer prepared FLASH). The RF power of a turbo-spin-echo sequence was increased by a factor of 5. Temperatures of the IUDs and the gel were measured during the MR examination. No deflection of the IUDs exposed to the magnetic field of 1.5 Tesla was detected. Under normal imaging conditions no temperature increase could be observed. Using an increased RF power, a maximal temperature rise of 0.4 degree C per examination was seen. No differences between the gel and the IUDs were observed, indicating that there is no specific heating of the tested IUDs.

Age dependency of the regional cerebral blood volume (rCBV) measured with dynamic susceptibility contrast MR imaging (DSC)

The changes of the regional cerebral blood volume (rCBV) with age were studied using dynamic susceptibility contrast MRI (DSC). We examined an unselected, random sample of 71 consecutive patients referred for work-up of suspected intracranial tumors (35 normal examinations, 36 tumors) with a standard 1.5 T clinical MR system. Determination of the rCBV was performed with a T2*-weighted simultaneous dual (SD) FLASH sequence (TR/TE1/TE2/alpha = 32/25/16/10 degrees, 55 images) after bolus injection of Gd-DTPA. Absolute quantification of the rCBV was achieved by normalizing the measured tissue concentration-time curves with the integrated arterial input function (AIF), which was simultaneously measured in the brain feeding arteries. The rCBV (mean +/- SD) was 8.4 +/- 2.9 ml/100 g and 4.2 +/- 1.7 ml/100 g in gray and white matter, respectively, with a decline of about 3% and 6% per decade for white and gray matter, respectively. We conclude that DSC using a SD FLASH sequence allows the simultaneous measurement of the AIF and the tissue concentration-time curve and thus an absolute quantification of the rCBV, which is the basis for interperson comparisons and follow-up studies.

Combined acetabuloplasty and varus derotation osteotomy in congenital dislocation of the hip. Long-term results

Twenty-two patients (33 hips) with congenital dislocation of the hip were examined at an average of 26 years after combined acetabuloplasty and intertrochanteric varus derotation osteotomy. Seventeen patients had no problems despite physically demanding jobs and sporting activities in some cases. The CE angle was improved to the lower end of the normal range. The shaft-neck angle was corrected by 31 degrees to 120 degrees. Restoration to the normal valgus subsequently occurred and we found no evidence of subcapital coxa valga. Although there was an increase in the neck epiphysis angle 5 years after operation indicating a horizontal shift in the epiphyseal plate, most cases had normal hip joints. The incidence of postoperative avascular necrosis of the femoral head was 6%, and we found no increase in femoral deformities. Our long-term results show that the combination of acetabuloplasty and femoral osteotomy has no disadvantages, and is the best way of achieving optimal centring of the femoral head and stabilisation of the hip.

[Heparin-induced thrombocytopenia. Results from the Comprehensive Hospital Drug Monitoring (CHDM) Bern/St. Gallen]

Of 23,520 consecutive hospitalizations from 1980-1988 (corresponding to 16,628 individual patients) in three departments of general internal medicine, 8261 were treated with heparin. All observations of patients displaying a probable, possible or questionable relationship of thrombocytopenia to heparin (administered i.v. or subcutaneously) were electronically collected by the CHDM program, revised on the basis of the primary case records and selected by standardized criteria. 13 of the 8261 patients exposed to heparin were considered to have a probable or possible HIT, corresponding to a frequency of 0.157%. In two of them severe thrombocytopenia was observed (corresponding to 0.024%) accompanied in one case by a white clot syndrome. Thrombocytopenia was defined as a platelet value below 100 x 10(9)/l and severe thrombocytopenia as one below 30 x 10(9)/l. In the literature we found slight, asymptomatic thrombocytopenia in < or = 1-8% of heparin treated patients. Our result of 11 out of 8261 (corresponding to 0.133%) is low, partly because the thrombocyte count was not controlled systematically, the heparin used was mainly produced from swine intestinal mucosa, and no antibody tests had been carried out. To prevent severe thrombocytopenia from heparin we propose monitoring the platelet count if the treatment is to be continued for more than 5 days. The newer low molecular weight heparins, all of swine origin, are much safer compared to the traditional preparations in regard to risk of HIT and white clot syndrome.

Glyburide-reversible cardioprotective effect of BMS-180448 is independent of action potential shortening

OBJECTIVE

We determine if action potential duration (APD) shortening and cardioprotection are separable phenomena in ATP-sensitive potassium channel (KATP) openers which protect ischemic myocardium via a glyburide-reversible mechanism.

METHODS

We determined the effect of the weakly vasodilating KATP opener, BMS-180448, and the less cardiac-selective cromakalim, on APD in normal, hypoxic or ischemic guinea pig papillary muscles or isolated hearts and compared their APD effects with their cardioprotective activity in isolated guinea pig hearts.

RESULTS

In isolated ischemic guinea pig hearts, cromakalim and BMS-180448 had similar cardioprotective potencies (EC25 of 3.2 and 3.3 microM, respectively, for increasing time to the onset of contracture). At 10 microM, BMS-180448 produced no APD shortening, yet was equally protective at this concentration compared to cromakalim, which produced profound APD shortening under either hypoxic or ischemic conditions. The cardioprotective effects of both compounds at 10 microM were abolished by 0.3 microM glyburide.

CONCLUSIONS

APD shortening is not correlated with cardioprotective activity for BMS-180448 and cromakalim while their cardioprotective effects are abolished by glyburide. These results suggest the possibility of reduced proarrhythmic activity in some KATP openers and that their cardioprotective activity is not associated with sarcolemmal KATP opening.

[Proprioceptive deficit following cruciate lesions--afferent disorder or compensatory mechanism?]

It was suggested that the ACL has not only mechanical functions but also acts as proprioceptive organ. In cruciate deficient knees pathological patterns of muscle control were found. These findings could be caused by a disturbed afferent signal from the disrupted ACL or by secondary changes in muscle innervation, which shall protect the instable knee against subluxation. 33 patients with unilateral operative ACL repair (21 cases with primary suture, 12 cases with autogenous ligamentum-patellae-reconstruction; average post op 36.5 yr) were examined clinically and with the KT 1000 arthrometer (MEDMETRIC Inc.). Patients history was evaluated by using the LYSHOLM score. During a cycling task the electromyographic activity was monitored from the thigh muscles (M. vastus lat. and med., lat. and med. hamstrings). In comparison to the ACL deficient patients, we tested 25 healthy subjects of same age and activity level. In the ACL group the following differences to the normals were found: the M. vastus lat. showed a significantly delayed onset, earlier end and shorter duration. M. vastus med. had the same pattern; the delayed begin of activity and the shorter duration were statistically significant. M. biceps femoris showed a significant later onset and shorter duration. So did the medial hamstrings; the differences, however, were not statistically significant. There was no significant difference between operated and healthy leg in the ACL group. By comparing the primary sutures and the ligamentum-patellae-reconstructions no significant differences were found. The instable patients (KT 1000 > 3 mm) of the ACL group showed more distinct differences in the EMG pattern than the patients with stable knee joints.(ABSTRACT TRUNCATED AT 250 WORDS)

[Primary stability of autologous and heterologous implants for intervertebral body spondylodesis]

In this study, we tested the stability of the xenograft SURGIBONE and of human iliac crest graft depending on the donor's bone density. The mean load bearing capacity of SURGIBONE was 4816 N, the compressive strength 32.8 N/mm2. This even exceeds the values given by the producer. Yet in clinical use the material caused problems by collapses or lysis of the graft. According to our results, those failures can not be explained by missing primary stability. Perhaps there is a immunogenic reaction of the host against the remaining protein as it once was proved for the "kielspan"-graft. The iliac crest grafts of donors with normal bone density had a load bearing capacity of 3397 N. Grafts of donors with reduced bone density of less than 60 mg/ml Ca-Equivalent showed reduced load bearing capacities of 2265 N. DEXA (Dual-Energy X-Ray Absorptiometry) seems to be suitable to scan preoperatively the iliac crest graft stability in order to recognize the danger of reduced stability by osteoporosis.

Shortening Z-osteotomy for the proximal phalanx of the hallux using axial guides

The shortening Z-osteotomy of the proximal phalanx of the hallux has been presented as an alternative to the Regnauld enclavement procedure for patients with the appropriate indications. In addition to sharing the same positive characteristics as the Regnauld procedure, the Z-osteotomy has technical and physiologic advantages. The advantages of the Z-osteotomy over the Regnauld include maintenance of the intrinsic attachments at the base of the proximal phalanx, less risk of avascular necrosis, less technical difficulty, and absence of complications associated with an autogenous bone graft. Also, it does not affect the sesamoid apparatus. Research and extended follow-up studies will continue at Lakewood Regional Medical Center. In the last year, one author has completed approximately 13 of these procedures. The postoperative results have been encouraging and successful with one exception. In one case, the increase of the hallux interphalangeal angle was probably caused by excessive tightening of the distal screw compared with the proximal screw.

[Frequency of antibiotics-associated colitis in hospitalized patients in 1974-1991 in "Comprehensive Hospital Drug Monitoring", Bern/St. Gallen]

In 3 divisions of internal medicine of teaching hospitals of the Comprehensive Hospital Drug Monitoring (CHDM) Foundation Bern/St Gallen, 42,920 patients consecutively admitted between 1974-1991 were investigated for adverse drug reactions. Of these 16,150 patients (38%) had received at least one systemically administered antibacterial drug during the hospital stay. Antibiotic-associated colitis included the following diagnoses: pseudomembranous colitis, hemorrhagic colitis and milder forms of colitis. We collected the data of these patients by searching for all diagnoses which might represent antibiotic-associated colitis (from the list of WHO adverse drug reaction terminology). 9 individual patients with one episode of probable antibiotic-associated colitis were found. In 5 of these cases, only one drug given during the hospital stay seemed to be implicated. An additional 32 patients were admitted with antibiotic-associated colitis in relation to treatment with the same groups of drugs before hospital admission. Based on the exposure pattern of the 9 patients with antibiotic-associated colitis compared to all patients exposed during hospital stay, we estimated the following frequencies related to the drug groups with at least 1,000 patients exposed: for all antibacterial chemotherapeutics 0.6/1000 (0.25-1.06); all penicillins 0.6/1000 (0.22-1.32), for benzyl-, phenoxy-, ureido-, isoxazolyl penicillins and methicillin 2.0/1000 (0.42-5.92) and aminopenicillin or analogues, with or without clavulanic acid 0.6/1000 (0.18-1.35). For cephalosporins the frequency is 1.4/1000 (0.17-5.12). Under sulfonamides combined with trimethoprim or related substances (5077 exposed patients) and fluoroquinolones (1043 exposed patients) no case was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic mapping of the breast: a new method for dynamic MR mammography

A dynamic contrast-enhanced MRI technique for whole breast examinations is presented. The fast kinetics of tissue response during and after constant-rate intravenous infusion of gadolinium diethylenetriaminopentaacetic acid was resolved using a strongly T1-weighted saturation recovery TurboFLASH sequence that makes it possible to acquire signal-time courses sequentially from 15 adjacent slices with a temporal sampling rate of 21 s. On the basis of the mathematically established and experimentally verified linear relationship between the measured saturation recovery TurboFLASH signal variation and the gadolinium diethylenetriaminopentaacetic acid concentration in the tissue, the signal-time courses were analyzed within the framework of pharmacokinetic modeling. In our study, the tissue response was parameterized adequately using an open linear two-compartment model. With this approach, the tissue specific information contained in the signal-time course can be described using only two parameters: an amplitude A, reflecting the degree of MR signal enhancement, and an exchange parameter k21, characterizing vascular permeability and perfusion of the tissue. A clearly arranged representation of the large amount of data (480 saturation recovery TurboFLASH breast images/examination) was accomplished by means of color coding of the computed parameters, resulting in one color-coded pharmacokinetic parameter map/cross-section.

Changes in muscular activity after knee arthrotomy and arthroscopy

The object of this study was to find out whether an arthrotomy of the knee would damage joint proprioception. Twenty patients who underwent arthrotomy, and 20 patients after arthroscopy, were tested on a modified ergometer and the electromyographic action of their quadriceps and hamstrings recorded. The quadriceps action started later and had a shorter duration (20 ms) after arthrotomy. The differences are statistically significant in intra-individual comparison both for vastus lateralis and medialis, in comparison with the normal group for only the vastus medialis. There were no significant differences in muscle control after arthroscopy. These results are in favor of preferring arthroscopy to arthrotomy whenever possible.

[Biomechanical principles of after-care in replacement of the anterior cruciate ligament]

The patellar tendon graft replacing the anterior cruciate ligament undergoes histomorphological and biomechanical changes. From literature we can estimate a force of 200 N to be a critical limit of graft load after ACL-plasty in humans. The comparison with the graft loads under various conditions provided the following conclusions: Unlimited passive motion of the knee joint can be done without risk. Early weight bearing is possible. Active extension exercise against gravity could damage the graft in the range of 0 to 20 degrees of flexion in some patients. A rehabilitation protocol has to regard these biomechanical principles. In a prospective study 74 patients underwent rehabilitation according to the protocol described. An extension contracture of more than 10 degrees was seen in 9 patients. In all cases it was due to a notch-impingement or a cyclops. One year after operation 57 patients had a follow up. The side to side-difference in anterior drawer measured with a KT-1000-arthrometer was less than 2 mm in 45 patients. Six patients had difference between 2 and 4 mm. In six patients the difference was more than 4 mm.